Prior to the release of Minecraft 1.3, when a player tried to issue a command and they didn't have op, "<player> tried command <command>" was outputted to the console. This was removed in Minecraft 1.3, the new output became "Unknown Command. Type "help" for help." This removal of a command name and arguments makes it impossible for server owners to figure out what command a player tried to use when needing to check their logs to deal with troublesome players who may have been trying to use bukkit commands and finding them gone decided to start griefing.